Seismic isolation system having damper type damping mechanism

ABSTRACT

The present invention provides a method for fixing an orthogonal angle of rollers in a seismic isolation system having a support mechanism by the rollers which are overlapped up and down and orthogonal to each other, Since a structure is shaken when a damping three of a damping mechanism exceeds seismic energy, a damping mechanism having a function of controlling and suppressing the damping force in accordance with the seismic energy is also produced. 
     In order to maintain the orthogonal angle of the rollers, retaining materials having slight clearances which allow rolling of the rollers are attached to orthogonal parts of the rollers so as to fix the orthogonal angle. Meanwhile, energy absorption when a linear steel material is wound around a cylindrical material and continuously deformed by a horizontal force serves as the damping force, and by changing an axial section area of the linear steel material, an energy absorbing amount is controlled. By interrupting the horizontal force so as to cancel the energy absorption, the energy absorption of the linear steel material is suppressed upon a swing range of a small earthquake, so that the damping three can he controlled and suppressed. The present invention provides such a damper type damping mechanism.

FIELD OF THE INVENTION

The present invention relates to a technique in which in a seismic isolation system proposed in Japanese Patent Application No. 2006-539143, a fixing mechanism of an orthogonal angle of top and bottom rollers in a roller type support mechanism of the top and bottom rollers which are orthogonal to each other, and a damper type damping mechanism having a function of controlling and suppressing a damping force are given to the seismic isolation system.

BACKGROUND ART

In order to keep away from damage to a structure by an earthquake, a method of making a structure strong is considered to be the best. However, no matter how strong the structure is, a physical risk due to falling and dropping of household goods and the like cannot be avoided unless shaking of the structure is suppressed,

As a method for solving this, in order to absorb shaking received from a ground, it is known to be effective to divide into a substructure such as a foundation and a superstructure serving as a structure to which seismic isolation is implemented, and construct a support function, a position repairing function, and a damping function between both the structures to form a seismic isolation system, so as to prevent shaking of the structure.

Although various seismic isolation systems are developed, few systems can be utilized with a general-purpose property for from light structures such as residential houses to large structures. Development of a system with a general-purpose property is desired.

In the existing seismic isolation system, rubber, lead, synthetic oil, synthetic resin, steel material, and the like are used as use materials, and highly-advanced techniques are required. in addition, a deteriorating material is included in the system, or a mechanism has an internal structure, so that parts thereof require precision.

Manufacture of the system requires specific manufacturers or specific materials, and highly-advanced processing techniques or special working machines are often required. A manufacturing amount is also small, so that a price becomes high, and the system is not widely used. Further, in a long use period, inspection from a specialist view, replacement of parts, and the like are also required, However, the internal structure is not easily inspected, and the system is not preferable in terms of maintenance.

Unless a damping function is given to a seismic isolation structure onto which a horizontal force at the time of a huge earthquake is applied by a damper or the like, the seismic isolation structure runs off the track, and sometimes causes excessive or unstable shaking. Thus, a damping mechanism is generally provided in the seismic isolation system.

The existing damping mechanism has a damping ability taking an energy absorbing amount of a generally-targeted maximum earthquake area as a standard. Thus, the damping ability based on a huge earthquake is excessive for a small earthquake force. When the damping function is provided, a horizontal force buffering function of a support mechanism which is an opposite function thereto is disturbed. Thus, in a case of a small earthquake, although the seismic isolation system is installed, the structure is shaken due to the excessive damping ability as a result. Therefore, a solution is desired.

In order to avoid such shaking, there is a need for controlling and suppressing the damping force in accordance with a magnitude of an earthquake. However, no method for mechanically simply controlling and suppressing the damping force is established.

CITATION LIST Non-Patent Document

[Non-Patent Document 1] Housing Bureau, Japan's Ministry of Land, infrastructure, Transport and Tourism, et al., “Commentary on Technical Criteria of Seismic Isolation Buildings, and Calculation Examples and Commentary thereof”, Engineering Books Co., Ltd., Dec. 20, 2000, pp.11-12, images 4 to 6.

[Non-Patent Document 2] “Responsive Control Structure Design Method”, in Japan Structural Consultants Association. ed., SHOKOKUSRA Publishing Co., Ltd., pp. 310-319, figures and images.

SUMMARY OF THE INVENTION Problems to be Solved by the Invention

In the present invention, a first object is to provide a seismic isolation system provided with a mechanism for preventing twist of rollers on a horizontal contact surface, the rollers being overlapped up and down while running in the X axis and Y axis directions and orthogonal to each other, the rollers serving as a support mechanism in the seismic isolation system, and maintaining an orthogonal angle of the rollers, so as to contribute to stable operation of a damping mechanism. Together with this object, a second object is to elucidate an operation principle capable of mechanically controlling and suppressing a damping force of the above damping mechanism and provide a new type of damping mechanism in the seismic isolation system.

Means for Solving the Problems

In the present invention, for achieving the object 1, in order to maintain an orthogonal angle of rollers (3) and (4) which are overlapped up and down and orthogonal to each other, a slight clearance allowing rolling of the rollers (3) and (4) is provided. Retaining materials (9) and (10) made of steel plates having U shape sections which do not allow displacement of the orthogonal angle are placed over orthogonal parts of the rollers (3) and (4) from the upper and lower sides in such a manner that open sides of the U shape sections face each other. Front end parts of the open sides are bent outward at a right angle, and holes for four combining bolts are formed on bent surfaces. By firmly combining contact surfaces of the retaining materials (9) and (10) with combining bolts (11), a fixing mechanism of the orthogonal angle capable of preventing twist of the rollers (3) and (4) is formed. By this mechanism, an operational environment of the damping mechanism is favorably arranged (Invention of claim 1).

In the present invention, for solving the above object 2, a configuration of the damping mechanism in the seismic isolation system provided with the above fixing mechanism is as follows.

That is, a linear steel material (14) serving as a plastic material is wound around an outer cylindrical material (13) freely fitted to a cylindrical material (12), and a damping force can be obtained by an energy absorbing function in accordance with dethrmation of the linear steel material (14) caused by relative deformation of the linear steel material (14) and the outer cylindrical material (13) (Invention of claim 2).

As an additional function of the above damping mechanism, by providing clearances (21) and (22) and giving a movement-free space to the cylindrical material (12) in addition to the relative displacement of the linear steel material (14) and the outer cylindrical material (13), horizontal displacement energy transmission between a substructure (1) and a superstructure (8) is interrupted, and the deformation of the linear steel material (14) wound around the outer cylindrical material (13) is stopped. Thus, the energy absorbing function is cancelled, so that energy absorption is suppressed (Inventions of claims 3 and 4).

By changing an axial section area of the linear steel Material (14), an energy absorbing amount may be changed so as to be controlled (Invention of claim 5).

Further, by a method in which the number of leftward winding and the number of rightward winding of the linear steel material (14) are the same, or the linear steel material has such a section area that an axial resistance force of the leftward winding direction and an axial resistance force of the rightward winding direction are the same, a couple of forces imposed on the outer cylindrical material (13) at the time of attachment is eliminated, so that twist of the outer cylindrical material is stopped. Thus, the operational environment of the damping mechanism can be stabilized (Invention of claim 6).

Effect of the Invention

As described above, the fixing mechanism of the orthogonal angle of the rollers and the damping mechanism according to the present invention, which are useful when applied to the seismic isolation system of the present invention can be formed with simple construction, used materials can be integrated into the steel material, and shapes of parts are simple, so that no complex shapes and internal structures are provided. Therefore, upon manufacture, when a steel material standardized in the market is processed by such means as cutting, bending, welding, and anti-rust coating by using a general-purpose working machine, the system of the present invention having a general purpose property for from light structures to large structures can be easily manufactured.

Moreover, for the constituent members of the system of the present invention, a deteriorating material or an expensive material is not used, or a special working machine, a special process, or cooperation of a specific material provider, a specific manufacturer, or the like is not required. Thus, the system can he manufactured at extremely low cost.

Further, in the seismic isolation system provided with the mechanisms of the present invention, deterioration of the constituent parts and a decrease in functions are hardly generated after start of use, and replacement of the parts and the like are not required in general. An operation state of the system can be visually confirmed from an outer appearance, so that various demands required for the seismic isolation system in which the functions have to he stably maintained over a long time can be sufficiently satisfied. Therefore, by installing the system of the present invention in a structure, an effect of preventing seismic disaster can be expected.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view by the line XX of FIG. 2 showing an embodiment of a seismic isolation system of the present invention;

FIG. 2 is a plan view showing an attachment state of major structural portions of the seismic isolation system of the present invention;

FIG. 3 is a detailed plan view of a fixing mechanism of an orthogonal angle, showing an attachment state of roller retaining materials in FIG. 2 (claim 1);

FIG. 4 is a sectional view by the line A-A of FIG. 2, showing the fixing mechanism of the roller orthogonal angle (claim 1);

FIG. 5 is a perspective view showing assembling of members of the fixing mechanism of the roller orthogonal angle (claim 1);

FIG. 6 is a detailed plan view showing attachment positions of major members of a damping mechanism in FIG. 2;

FIG. 7 is a sectional view by the line BB of FIG. 2, showing the attachment positions of the major members of the damping mechanism;

FIG. 8 is an elevation view showing a cylindrical material and a support hole of a bracket (claim 2);

FIG. 9 is an elevation view showing a movement-free clearance (21) between the cylindrical material and an outer cylindrical material (claim 3); and

FIG. 10 is an elevation view showing a movement-free clearance (22) between the cylindrical material and a support hole of the bracket (claim 4).

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Hereinafter, an embodiment for carrying out the present invention will be described based on FIGS. 1 to 10.

When a superstructure (8) shown in FIG. 1 is displaced in the horizontal direction, bottom and top rollers (3) and (4) which are orthogonal to each other, serving as a support mechanism are rolled in directions that the rollers respectively cover, the X axis direction and the Y axis direction, so as to buffer a horizontal force. At this time, when a bias force is imposed on the superstructure, an orthogonal angle of the rollers (3) and (4) shown in FIG. 2 is twisted, and a crossing angle of a cylindrical material (12), an outer cylindrical material (13), and linear steel materials (14) serving as a damping mechanism is also twisted, so that operations of the damping mechanism are badly influenced.

Thus, in the present invention, in order to maintain he orthogonal angle of the rollers (3) and (4) which are overlapped up and down and orthogonal to each other, serving as the support mechanism shown in FIG. 5, a slight clearance allowing rolling of the rollers (3) and (4) is provided. Retaining materials (9) and (10) made of steel plates having U shape sections which do not allow displacement of the orthogonal angle are placed over orthogonal parts of the rollers (3) and (4) from the upper and lower sides in such a manner that open sides of the U shape sections face each other in orthogonal directions. Front end parts of the open sides are bent outward at a right angle, and holes for four combining bolts are formed on bent surfaces. Contact surfaces of the retaining materials (9) and (10) are firmly combined with combining bolts (11), so as to serve as a fixing mechanism of the orthogonal angle of the rollers (3) and (4).

Thereby, the axial direction of the linear steel materials (14) is always maintained at a right angle to the cylindrical material (12) shown in FIG. 6, serving as the damping mechanism, A clearance (21) between the cylindrical material (12) and the outer cylindrical material (13) shown in FIG. 9, and balance between contact surfaces of the cylindrical material (12) and attachment support holes (22) of brackets (15) shown in FIG. 10 are ensured, so that conditions for stably operating the damping mechanism can be satisfied.

When a substructure (1) and the superstructure (8) are relatively displaced in the horizontal direction due to the horizontal force imposed on the superstructure (8) shown in FIG. 1, the superstructure and the substructure are displaced in the vertical direction by the rollers (3) and (4) rolled on recessed roller receivers (2) and (6). At this time, since the brackets (15) fixed to the substructure shown in FIGS. 6 to 8 are provided with attachment support holes (20) having vertical clearances required for upward and downward movement of the cylindrical material (12), the brackets support the cylindrical material (12.) moved upward and downward.

Meanwhile, horizontal displacement is also caused between brackets (16) fixed to the cylindrical material (12) or the outer cylindrical material (13) and the superstructure (8), and members of the linear steel materials (14) wound around the outer cylindrical material (13). At this time, regarding the linear steel materials (14) wound around the outer cylindrical material (13), one ends are deformed from a round form to a straight line state, and the other ends are deformed from a straight line to a round form state. Thus, an energy absorbing effect is generated. A mechanism for mechanically generating the energy absorbing effect from this horizontal force serves as a basic damping mechanism of the present invention.

In the present invention, a movement-free effect of the clearances (21) and (22) and the cylindrical material (12) shown in FIGS. 9 and 10 is further added to the above basic damping mechanism. Here, the movement-free effect is as follows.

That is, regarding a horizontal force of a small earthquake generated in the superstructure (8), when an energy absorbing amount of the basic damping mechanism is more than an energy amount of the horizontal force, the superstructure (8) is shaken until the energy amount of the horizontal force exceeds the energy absorbing amount of the damping mechanism. In order to avoid this shaking, a method of interrupting seismic energy transmitted to the linear steel materials (14) is considered. Thus, the movement-free clearances (21) and (22) for interrupting the horizontal force are produced between the inner cylindrical material (12), the outer cylinder (13), and the brackets (15) serving as a transmission mechanism of the horizontal force.

While the cylindrical material (12) is freely moved in the horizontal direction by this clearance part, a damping function is cancelled, and the outer cylindrical material (13) does not receive a rotation force, so that energy absorption of the linear steel materials (14) is suppressed.

This produces a state that upon a small earthquake in which the cylindrical material (12) and the outer cylindrical material (13) are freely moved and swung between the clearances, the damping function does not work but only a horizontal force buffering function by the support mechanism of the rollers works. Thereby, a function of mechanically suppressing a damping force upon swing of a small earthquake area is added to the basic damping mechanism, so that a targeted damping mechanism capable of suppressing shaking of a small earthquake is obtained.

When the substructure (1) and the superstructure (8) are relatively displaced in the horizontal direction, in the present invention, in the basic damping mechanism of energy absorption generated in winding parts of the linear steel materials (14) and the outer cylindrical material (13), by continuously changing axial section areas of the linear steel materials (14), the energy absorbing amount of the linear steel materials (14) can be continuously changed. Thereby, a function of mechanically controlling the damping force in accordance with swing in the axial direction of the linear steel materials (14) can be obtained. Thus, this is added to the above basic damping mechanism in the present invention.

In a case where odd numbers of the linear steel materials (14) are wound around the outer cylindrical material (13) in the damping mechanism shown in Fig, 6, in crossing parts in which the linear steel materials (14) are wound around the outer cylindrical material (13), the linear steel materials are placed in the opposite axial directions not on one straight line, so that a couple of forces is generated at the time of attachment. The outer cylindrical material (13) is twisted by this couple of threes. Therefore, in the present invention, in order to cancel the couple of forces, the number of rightward winding and the number of leftward winding of the linear steel materials (14) are the same, or the linear steel materials have such section areas that an axial resistance force of the leftward winding direction and an axial resistance force of the rightward winding direction are the same. Thus, an influence of the couple of forces can be eliminated, so that an operational environment of the basic damping mechanism can be favorably arranged.

As in the present embodiment described above, the present invention provides a new type of damping mechanism having a concise structure but achieving a configuration for mechanically suppressing and controlling the damping force of the damping mechanism with a simple method.

REFERENCE NUMERALS

1: Foundation of substructure

2: Recessed roller receiver (bottom)

3: Roller (bottom)

4: Roller (top)

5: Projection plate

6: Recessed roller receiver (top)

7: Mount of superstructure

8: Structure of superstructure

9: Roller retaining material (bottom)

10: Roller retaining material (top)

11: Roller retaining and combining bolt

12: Cylindrical material

13: Outer cylindrical material

14: Linear steel material

15: Bracket of cylindrical material 12

16: Bracket of linear steel material 14

17: Support hole of bracket 15 of “claim 4”

18: Material for preventing dropping from bracket 15 to be fixed to outer end of cylindrical material 12

19: Fixing bolt for bracket 15 and foundation

20: Support hole of bracket 15 of “claim 2” and “claim 3”

21: Movement-free clearance between cylindrical material 12 and outer cylindrical material 13 of “claim 3”

22: Movement-free clearance between support hole 17 of bracket 15 and cylindrical material 12 of “claim 4” 

1. A seismic isolation system to be arranged between an upper surface of a substructure and a lower surface of a superstructure as a seismic isolation mechanism, having top and bottom rollers which are orthogonal to each other, the seismic isolation system comprising: a fixing mechanism of an orthogonal angle of the rollers, in which retaining materials for allowing rotation of the top and bottom rollers and retaining the orthogonal angle of the rollers are attached to outer sides of roller crossing parts which are other than contact parts of the rollers.
 2. The seismic isolation system according to claim 1, comprising: a damping mechanism in which: brackets supporting both ends of a linear steel material and brackets supporting both ends of a cylindrical material are fixed to the upper surface of the substructure and the lower surface of the superstructure so as to face each other; the bracket of the cylindrical material has a support hole allowing upward and downward movement of the cylindrical material; the cylindrical material is rotatably and freely fitted to an outer cylindrical material, and has length which is, preparing for horizontal displacement of the superstructure, displacement width thereof or more, and length of the outer cylindrical material or more; and the linear steel material is wound around the outer cylindrical material, both the ends of the steel material are fixed to the brackets of the steel material in opposite directions which are orthogonal to the cylindrical material, and fixing positions of the brackets of the steel material are set to be width which is more than the horizontal displacement width of the superstructure from the outer cylindrical material.
 3. The seismic isolation system according to claim 2, wherein a clearance is provided between an outer diameter of the cylindrical material and an inner diameter of the outer cylindrical material in the damping mechanism.
 4. The seismic isolation system according to claim 2, wherein a clearance in the horizontal direction is provided between the support hole of the bracket of the cylindrical material and an outer diameter of the cylindrical material supported on the hole in the damping mechanism.
 5. The seismic isolation system according to claim 3, wherein an axial section area of the linear steel material is continuously changed in the damping mechanism.
 6. The seismic isolation system according to claim 3, wherein the number of leftward winding and the number of rightward winding of the linear steel material are the same, or the linear steel material has such a section area that an axial resistance force of the leftward winding direction and an axial resistance force of the rightward winding direction are the same in the damping mechanism.
 7. The seismic isolation system according to claim 4, wherein an axial section area of the linear steel material is continuously changed in the damping mechanism.
 8. The seismic isolation system according to claim 4, wherein the number of leftward winding and the number of rightward winding of the linear steel material are the same, or the linear steel material has such a section area that an axial resistance force of the leftward winding direction and an axial resistance force of the rightward winding direction are the same in the damping mechanism.
 9. The seismic isolation system according to claim 5, wherein the number of leftward winding and the number of rightward winding of the linear steel material are the same, or the linear steel material has such a section area that an axial resistance force of the leftward winding direction and an axial resistance force of the rightward winding direction are the same in the damping mechanism.
 10. The seismic isolation system according to claim 7, wherein the number of leftward winding and the number of rightward winding of the linear steel material are the same, or the linear steel material has such a section area that an axial resistance force of the leftward winding direction and an axial resistance force of the rightward winding direction are the same in the damping mechanism. 